Fusible link and strut



L. M. LEWIS. FUSIBLE LINK AND STRUT. APPUCATION FILED MAR. 26, 1920.

1,379,195. Patented May 24,1921.

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LEROY M. LEWIS, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR To Q LEWIS, OF BALTIMORE, MARYLAND.

FUSIBLE LINK AND STRUT.

Specification cf Letters Patent.

Patented May 24, 1921.

To all whom it may concern:

Be it known that I, LEROY M. Lewis, a citizen of the United States, and a resident of the city of Philadelphia, county of Philadelphia, and State of Pennsylvania, have invented certain new and useful linprovements in Fusible Links and Struts, of which the following is a specification, reference being had to the accompanying drawing, forming a part hereof.

My invention relates to fusible links and struts of the type used in fire extinguishing systems, fire doors, fire alarms and other and similar devices wherein it is desired to hold certain parts of the mechanism, to

which the'links or struts are applied, in assembled relation until sufficient heat is pres ent in the vicinity of the contrivance to cause the link or strut components to become separated by the fusing or melting of the fusible material normally uniting the component parts together.

My invention relates more particularly to a new and useful means adjunctive to links and struts of the type above mentioned and which will indicate from mere inspection the completeness and the operativcness of the link or strut.

Among the objects of my invention is to provide a construction of the character men tioned whereby the link or strut may be quickly and efiiciently thrown apart immediately upon the fusing of the fusible binding substance.

Another object is to so construct a device that the component parts will be normally restrained from relative movement by the use of a rigid strain or restraining member which, upon fusing of the binding material, acts to separate the component parts in a lateral direction, but which normally acts to prevent any creeping or cold-flow action that would interfere with the proper functioning of the device.

A further object is to provide means to prevent the misplaccment or even the separation of the parts during the assembling thereof and to therefore insure against the premature operation of the device by reason of incorrect or inaccurate assembly of said parts.

A. still further object is to also provide means which is of utility to indicate upon inspection the presence of an essential part the link or strut useless.

of the assembly and hence the operativeness of the device.

Other objects of my invention will more fully appear from the following specification and in the accompanying drawing.

In prior structures it has been found that links or struts of the type mentioned frequently fall or operate prematurely, usually from the fact that in assembling the parts the workman at the factory permits an essential element, such as a key, strain member or the like, interposed between the plates. to slide or fall out from therebetween and fills the space or socket, provided for such member, with solder or fusible material, the solder usually protruding more or less from the edges of the plates and from the ends of the key socket. It will be apparent that under such conditions there is nothing to indicate whether or not the key is contained within the socket, and consequently an omission of the key or strain element will render Such device may be subjected to all the careful and proper inspections desired yet inasmuch as the fusible material completely fills and hides the spaces that should be occupied by the key or similar element, it is usually assumed that the key is present and is covered by said fusible material, the defective link or strut thus passing inspection without any detection of its actual defect.

If, on the other hand, the key be properly assembled in place within the socket provided between or in the plates, it frequently occurs that the solder or fusible material is improperly appli d in respect to the key and plates so that it does not effectively seal the ends of the socket at the ends of the key and it is accordingly possible, at any time, for the key to become separated from the plates without it being observed, whereupon when the link or strut is attached to a sprinkler head it will not be able to withstand the strains placed upon it by the water pressure in the system, and consequently will prematurely operate, a condition which is very annoying and objectionable as well as causing considerable damage to goods with which the water comes in contact.

Moreover it has been discovered, even though a link or strut of the type mentioned be completely assembled and properly mounted in a sprinkler head, the fusible material at the ends of the socket may become detached or fall out by the vibrations of the pipes, such as, water-hammers chattering and the like, whereby the key may be come gradually displaced and finally separated from the rest of the link or strut structure, the solder between the plates temporarily retaining the plates in unseparated condition but soon resulting in a premature operation of the sprinkler head.

Iy invention, therefore, involves the idea of constructing the fusible link or strut with means adapted to avoid the conditions mentioned above and which will respond only in the presence of heat sufficient to fuse the fusible material and to properly operate at the time and in the manner in which it is intended. I accomplish this by making the key socket of the closed type wherebythe key is'entirely inclosed or nested within the socket space provided between or within deflected or offset portions of the link or strut plates.

One of the important features of my invention is to provide the key or strain member with visible projecting indicators which are readily perceived from the exterior of the link or strut structure and which act as a positive indicator of the completeness of the structure. The underwriters now require that all structures of the type mentioned above should be provided with means indicating that the link or strut is complete and that no essential element thereof may be absent or the fact of its absence be hidden from view-in the manner above indicated in the previous structures.

To this end my invention consists of the features of novelty that l hereinafter describe with reference to the accompanying drawings forming a part hereof and in which; 7

Figure 1 is a view in side elevation of a link constructed in accordance withmy invention,

Figs. 2 and 3 are respectively vertical sectional and side elevational views of the link shown in Fig. 1,

Figs. 4c and 5 are respectively top plan and side elevational views of the key or strain member included in the link structure shown in Figs. 1, 2 and 3,

Figs. 6 and 7 are views respectively in elevation and longitudinal section of another form of link structure,

Figs. 8 and 9 are similar views of still another form,

Figs. 10 and 11 are similar views of a still further form, and,

Fig. 12 is a sectional view of a further construction.

The link or strut forming the subjectmatter of the present invention embodies in the main'three elements, to wit, two preferably substantially flat members or plates adapted to be connected together by their adjacent faces with fusible material or solder and a pressure sustaining or restraining member or key interposed between said plates and acting to normally prevent relative movement of said plates until the fusible material has become sufficiently fused to per mit. said key to operate to separate said plates. in one of the forms, however, three plates are used but the assembly and the functioning thereof is analogous to the structures provided with merely two plates as will appear more fully hereinafter.

As illustrated, my improved links and struts comprise, in the preferred form shown in Figs. 1 to 5 inclusive, a'pair of substantially rectangular flat plates 1 and 2 each respectivelyprovided near one end thereof with the apertures 3 and 1 and at the other end thereof with notches 5 and 6. These plates are adapted to be placed together face to face and with the apertured end of one adjacent the notched end of the other, so that the apertured ends'extend in opposite directions with the aperture of one plate registering with the notch of the other plate. The aperturesB and 1 are adapted to receive the parts to be connected to the link when the latter is assembled for operati on, such as the projecting lever arms of the members of a two-part toggle type of strut or lever arrangement frequently used in sprinkler heads.

The plates 1 and 2 may be provided with laterally bent or deflected portions 7 and 8 which form therebetween a substantially 1 rectangular form of socket of a length less than the width of the plates, with a shoulder or support 9 formed on the plate 1 and a similar shoulder 10 formed on the plate 2. Between the laterally bent portions 7 and 8 and the shoulders 9 and 10 is located a key member 11 which is of substantially rectangular form with the exception of its central portion and is adapted to lit in the socket a slight inclination to the planes of the plates 1 and 2 whereby as one plate moves longitudinally relatively to the other the key will be caused to rock upon the shoulders 9 and 10 to a horizontal position whereby'the plates will be separated from each other.

One of the plates, as for example plate 2, may be provided in the bent portion 8 thereof with an aperture 12 of any suitable'form but preferably of rectangular shape. The key 11 is provided at its central portion thereof with a laterally bent or deflected portion or projection 13 of preferably angular form. This projecting portion is 10- catee in the link or strut structure so as to project through the opening12 out of contact with or in spaced relation to the edges of said opening andextending beyond the plane of the surface 14 of the bent portion 8 so that the ridge or external portion 15 of the bent portion 13 will protrude exteriorly of the solder 17 filled into the space provided by the opening 12, the ridge or projection 15 being of utility to indicate the presence of the key within the socket of the plate assembly so that upon inspection it may be determined with certainty whether or not the link or strut structure is complete and includes the key or strain member which is a very essential element in this type of device. The key is formed preferably of sheet metal by stamping out in a diepress and is first cut in substantially rectangular form then centrally deflected to provide the angular projection 13 and the ridge 1:) thereof. It is also found convenient to remove side portions of the projection 13 by beveling or cutting off at angle the ends thereof as clearly shown at 16 in Figs. 2, 3 and 4: of the drawin By so shortening the length of the ridge 15 the length of the opening 12 may be accordingly made of less extent so that, as the key is caused to rock upon the shoulders 8 and 9 in the socket formed between the plates, the ends of the ridge 15 will be able to clear the ends of the opening 12; thereby avoiding any possibility of interference with a proper and complete operation of the link structure upon the fusing of the fusible material between the plates.

llusible material ll" is usually located between the plates 1 and 2 as well as in the free spaces included between the key and the plates in the socket formed therebetween.

It will be further observed that the socket portion formed in each plate member 1 and 2 does not extend the full width of the plates but terminates at short distance from the edges 18 and 19 of the plates 1 and 2 whereby the ends 20 and 21 of the key member will be adapted to abut against or contact witn the ends 22 and 23 of the socket formed between the plates, as is clearly shown in liig. l of the drawing. By providing the socket with the ends 22 and 23 as shown, a lon .itudinal movement of the key 11 will be p vented, the same being completely housed 1- nested betv. .i the plates and prevented from separation from the plates.

In operation the structuremay be suspended upon the ends of a pair of arms of a toggle type strut so that there is a normal tendency to move the plates 1 and 2 in the direction of the arrows shown in 2, the shoulders 9 and 10 hearing against the lat eral edges of the strain receiving portions of the key 11. lnasmuch as the key is in in- (lined position to the line of strain tending to more the plates 1 and 2 relatively longitudinally there is a component force tending to rock the key laterally and to force the plates 1 and 2 apart, the solder 17 being sufllcirnt to restrain this action so long as the to draw away from each other and to be thrown apart, the projection 13 on the key being withdrawn through the opening 12 of the plate 2 without interference therewith.

lleferring to the form of structure shown in Figs. 6 and 7 l have shown therein a central plate 24: and side plates 25 and 26, the latter two being substantially of the same form. The plate 24: is provided at its lower end with an opening 27 in register with notches 23 and 529 provided in the lower ends of the plates 25 and 26 respectively, while at the upper end of the plates 1.15 and 26 are provided openings or apertures 30 and 31, respectively, in register with a notch 32 provided in the upper end of the central plate 2 1. The plates 25 and 26 may be provided with flared portions 33 and 34 between which may be included a bearing member 35 of relatively hard material or of fusible material as desired.

The central plate is provided with a central aperture d6 and the plates 24 and 25 are 36 and 37, of substantially hemispherical form, so as to include therein and therebetween a hall 38 of substantially spherical form. The socketl portions 36 and 3? are provided with apertures 39 and 4:0 through which may extend visible indicating projections d1 and 4-2, preferably integrally formed with the ball 38 and with the ends thereof projecting a suitable distance beyond the external surface of the solder 4-3 and 44C filled in the. apertures 39 and to, as is clearly shown in Fig. 7. Solder 45 is included between the plate members and the ball in the usual manner.

In the operation of this form of device the central plate tends to move downwardly and the side plates tend to move upwardly, the upper edge of the aperture 16, bearing against the ball 38 tending to move the same downwardly. is soon as the fusible material 49 melts or fuses, the ball 38 is forced downwardly relative to the plates 25 and 26 against the surfaces 4;? and 48 thereby causing the plates 25 and 26 to separate laterally, the ball 38 gassing downwardly between the lower ends of the plates 25 and 26 and the projections 41 and d2 being withdrawn through the apertures 39 and d0. The upper end of the plates 33 and 34 may coact with the member 35 so that the latter will permit the separation of the ends 33 and 34 later than the separation of the lower ends of the plates 25 and 26 whereby the memp: ovided with laterally bent socket portions 7 her acts more or less like a hinge at the start of the separation of the link elements.

7 Referring to the structure shown in Figs- 8 and 9 the same comprises adjacently located plates 49 and 50 each provided at erally reflected portions 55 and 56 provided with preferably rectangular aaertures 57 and 58. l vithin the socket provided between the portions and 56 is located a key 59 of polyhedric form with the ends 60 and 61 thereof in the form of wedges or pyramids. The key may be provided with laterally extending indicating projections 62 and 63 extending through. the apertures 52' and 58 out of contact with the edges thereof and with the ends of the projections 62 and 63 protruding beyond the outer surface of the solder 6% and 65 filled into the apertures 5'? anl 58 so as to be visible to the outside, as is clearly shown. in 9. The plates and the key are united by fusible solder 66. I

In the operation of this type of link, the plates 49 and 50 normally tend to move longitudinally relative to each other in the direction of the arrows, shown in Fig. 9 whereby the tapered ends 60 and 61 of the key operate as entering wedges between the plates when the fusible material 66 melts, so as to cause a lateral separation of the plates. As the plates are laterally moved accordingly, the edges of the openings 5'? and 58 are adapted to clear by the ends of the projections 62 and 68 provided on the key 59.

Referring to the structure shown in Figs. 10 and 11 l have shown therein a pair of plates 67 and 68 provided with socket portions 69 and 70 of substantially semi-cylindrical form adapted to include a solid cylindrical key 71 in a substantially upright position as shown in Fig. 10. lhe plates 68 and 69 areprovided with apertures 72 and -73 and notches 74c and '6' 5 as in the forms described above. The socket portions 69 and 70 may be provided with apertures 7 6 and 77 through which normally project the visible projections Y8 and 79, preferably formed integral. with the key "[1, the open- .4'6 and 77 being filled with solder 80 and 81, as shown. The plates and the key are united by solder 82.

In the operation of this device, when the solder 82 is caused to fuse the plates 67 and 68 first move longitudinally whereupon the key 71 is caused to rock within the socket portions 69 and 70 so as to cause the plates 67 and 68 to separate laterally. During such movement the fusible projections 78 and 79 will be caused to be withdrawn through the apertures 76 and 77 respectively. The projections 78 and 79 normally project a suitable distance beyond the eX- terior surface of the solder 80 and 81 so as to prev visible means indicatingthe pres once of the key within the socket.

ln Fig. 12 l have shown a link utilizing a cylindrical. key in substantially transverse position relative to the plates thereof, this link comprising a pair of plates 83 and 84: provided with apertures 85 and 86 and f and 88 as in the forms above described. Both plates are provided with laterally extending socket oortions 89 and 90 between which is located a cylindrical key 2 The socket portions 89 and 90 are provi ed with apertures 92 and 98 which are preferably of rectangular form and disposed diametrically opposite each other on a line at substantially 4E5 to the plane of the plates 83 and 84-. The key 91 is prod with laterally extending visible procal key 91, and out of contact with the edges of said openings, as is clearly shown in Fig.

12. The plates 83 and 84 and the key 91 are normally held together by fusible solder 96.

the operation of this device, when the solder 96 fuses, the plates 83 and 84: first more longitudinally whereby the socket portions and 99 will be caused to ride over the curved surface of the pin 91 and then to be laterally separated from each other, projections 94 and being withdrawn through the apertures 92 and 93without interfering with the relative movement of the plates 83 and 84L.

In the forms shown in Figs. 6 to 12 inelusive l have shown the key member provided with pair of visible projections but it is to be understood that the use of two projections is not essential but the use of but a single projection suflicient or on the other hand if desired a larger number of projections that two may be utilized. In the several embodiments disclosed the visible projection is so located through an aperture as to project substantially beyond the exterior surface of the fusible material normally filling; the aperture so that the same may be visible for inspection at any time whether before or after assembl of the link or strut. The appearance of such projecttion will always indicate with certainty that the key member is present within the socket provided between the plates of the links structure sothat no link will be assembled with merely a quantity of fusible material in the key socket space without the presence of tie key or in which event the same will be readily detected by reason of the absence of the indicating projections.

tion of adjacently located plates provided with socket portions, a strain member fitting within said socket portions between said plates, said strain member having an indicazing projection extending laterally through an aperture provided in one of said plates, said projection being out of contact vith said plates and projecting beyond the plane of the external surface of said apertured plate, and fusible material located b tween said plates for binding the same together and for maintaing the plates and the strain member in fixed relative position un til fused by heat.

2. In a fusible link or strut, the combination of a pair of plates provided with socket portions and a strain member located in said socket portions, said strain member provided with an indicating projection extending through an aperture provided in one of said socket portions, said projection be ing spaced from the ends of said strain member and out of contact with said plates and fusible material between said plates for binding the same together and for maintaining said strain member in fixed relative position until said material is fused by heat.

In a fusible link or strut, the combination of a pair of adjacently located plates provided with laterally deflected socket portions and a strain member fitting within said socket portions, said strain member pro vided with an integrally formed laterally extending indicating projection extending through and beyond an aperture provided in one of said socket portions, said projection being out of contact with said plates and fusible material between said plates for binding said plates together and for holding said plates and said strain member in fixed relative position until said material is fused by heat.

4. In a fusible link or strut, the combination of a pair of plates provided wlith socket portions and a strain member fitting into said socket portions, said strain member provided with an integrally formed laterally extending indicating projection spaced from the ends of said strain member and extending through an aperture provided in one of said socket portions, said projection beingout of contact with said plates and fusible material between said plates for binding said plates together and for retaining said plates and salt restraining member in 'Xed relative position until fused by heat.

In a fusible link or strut, the combination of a pair of plates provided with socket portions and a strain member fitting in said socket portions between said plates, said strain member provided with an-integrally formed substantially V-shaped laterally extending indicating projection in spaced relation with respect to the ends of said strain member, and extending through an aperture provided in one of said socket portions beyond the external surface of said socket portion, said projection being out of contact with said plates and fusible material between said plates for binding said plates together and for retaining said plates and said strain member in relative position until fused by heat.

6. In a fusible link or strut, the combination of a pair of plates provided with socket portions, a strain member fitting in said socket portions between said plates, said strain member provided with an integrally formed substantially V-shaped projection spaced from the ends of said strain member and with the sides or edges of said projection tapered, said projection extending through and beyond an aperture provided in one of said socket portions and out of contact with said plates, and fusible material located between said plates for binding said plates together and for retaining said plates and said strain member in fixed relative position until fused by heat.

7 A key for fusible links and struts comprising spaced strain portions and intermediate integral formed laterally projecting V- shaped portion, said ll-shaped portion having its sides and edges tapered, said tapered projecting portion being spaced from the ends of said key.

8. In a fusible link or strut, the combination of a pair of plates provided with a keyway between said plates, one of said plates provided with an aperture opposite said keyway and spaced from the lateral edges of said plates, a key in said keyway provided with a laterally bent portion extending through said opening and projecting beyond the exterior surface of the plate provided with said opening and fusible material between said plates and in said opening for binding said plates together and for retaining said plates and said key in fixed relative position until said material is fused by heat.

9. In a fusible link or strut, the combination of a pair of plates provided with a keyway between said plates, one of said plates provided with an opening intermediate the ends of said plate and keyway and opposite said keyway, a key located in said keyway and adapted to receive the strain tending to part said plates, said key being provided with laterally bent portion opposite said opening and extending through said opening to the exterior of the plate provided with said opening and out of contact with said plate, said projection being visible at the exterior of said plate when said aperture is filled with fusible material, and fusible material between said plates for binding said plates together and for retaining said plates and said key in relative position until said material is fused by heat.

10. In a fusible link or strut, the combination of a plurality of plates arranged in sub stantially parallel relation, fusible material between said plates for binding said plates together, said plates provided with apertured and socket portions for the inclusion of a strain member, a strain member located in said socket portion, said strain member being provided with a laterally extending portion projecting through an aperture provided in one of said plates and extending. exteriorly thereof for visibility, said laterally extending portion being located in spaced relation to and out of contact with said apertured plate, and fusible material in said aperture.

11. In a fusible link or strut, the combination of a plurality of plates normally held together with fusible material, said plates provided with socket portions intermediate the ends thereof, a strain member located in the socket formed by said socket portions, said socket portions provided with apertures, said strain member provided with laterally extending projections extending through said apertures and out of contact with said plates, said apertures being filled with fusible material and the ends of said projections extending exteriorly of said solder in said apertures.-

In witness whereof I have hereunto set my hand this 22nd day of March, 1920.

LEROY M. LEWIS. 

